1. Field of the Invention
The present relates invention relates to capillary electrophoresis and more particularly to sample preparation for electrophoresis.
2. Description of Related Art
Capillary electrophoresis is a high resolution, high sensitivity method for preparation and detection of organic analytes in mixtures. Typically, the sample mixture is introduced into one end of a capillary tube filled with buffer solution, polyacrylamide gel, or other types of separation support medium. A high voltage potential is applied across the ends of the capillary tube to cause separation of the sample mixture into various species of analytes. Analytes of the same species are resolved into bands as separation takes place. A detector detects the presence of the bands.
One of the limitations of prior art capillary electrophoresis processes is the extremely small amount of sample which can be used without degrading the resolution of the separated bands. When a large amount of sample is used, the bands are broader and the spacings between bands are narrower. Portions of adjacent bands may overlap. It would be difficult for the detector to resolve two overlapped bands. Thus, the volume of sample used is typically in the order of several nanoliters. However, when a small volume of sample is employed, and the analytes of interest are present in low concentration in the small volume, the volumes of the analytes of interest are so small that it represents a major limitation on the detectability of the analytes.